Pauli Paramagnetism of Stable Analogues of Pernigraniline Salt Featuring Ladder-Type Constitution

2019 ◽  
Vol 142 (1) ◽  
pp. 641-648 ◽  
Author(s):  
Xiaozhou Ji ◽  
Haomiao Xie ◽  
Congzhi Zhu ◽  
Yang Zou ◽  
Anthony U. Mu ◽  
...  
Keyword(s):  
1995 ◽  
Vol 50 (6) ◽  
pp. 905-912 ◽  
Author(s):  
Sascha Broil ◽  
Wolfgang Jeitschko

The title compounds have been prepared by annealing cold-pressed pellets of the binary nitrides LnN and CrN. Well developed crystals were obtained by recrystallization of the binary or prereacted ternary nitrides in a Li3N flux. Their structures were determined from single-crystal diffractometer data. C e2CrN3 has a U2CrN3 type structure: Immm , a = 379.0(1), b = 340.4(1), c = 1251.7(2) pm, Z = 2, R = 0.012 for 383 structure factors and 16 variables. The atomic positions of this structure are similar to those of U2IrC2 and K2NiF4. The structure may be rationalized to a first approximation with the formula (Ce+4)2[CrN3]8−. The chromium atoms are in a distorted square-planar nitrogen coordination. The CrN4-squares are linked via corner-sharing nitrogen atoms, thus forming infinite, straight - N - CrN2- N - CrN2- chains. The cubic structure of La3Cr10−xN11 (a = 1298.2(1) pm ), Ce3Cr10−xN11 (with a small homogenity range; a = 1284.3(1)-1286.1(3) pm ), and Pr3Cr10−xN11 (a = 1289.1(2) pm ) was determined for the lanthanum compound: Fm 3̄ m , Z = 8, R = 0.027 for 189 F values and 18 variables. One chromium site was found to have an occupancy of only 80.9(5)% resulting in the composition La3Cr9.24(1)N11. The nitrogen atoms occupy four atomic sites. Three of these have octahedral environments (6 La, 3 La + 3 Cr, 2 La + 4 Cr), the fourth one is surrounded by eight chromium atoms forming a cube. The chromium atoms are tetrahedrally coordinated by nitrogen atoms, and these CrN4-tetrahedra are linked via common corners and edges to form a three-dimensionally infinite polyanionic network. In addition the chromium atoms with oxidation numbers of about 2 to 3 form numerous Cr - Cr bonds, which allow to rationalize the Pauli paramagnetism of the compound.


2017 ◽  
Vol 72 (8) ◽  
pp. 609-615
Author(s):  
Lukas Heletta ◽  
Stefan Seidel ◽  
Christopher Benndorf ◽  
Hellmut Eckert ◽  
Rainer Pöttgen

AbstractThe gallium-containing Heusler phases ScRh2Ga, ScPd2Ga, TmRh2Ga and LuRh2Ga have been synthesized by arc-melting of the elements followed by different annealing sequences to improve phase purity. The samples have been studied by powder X-ray diffraction. The structures of Lu0.97Rh2Ga1.03 (Fm3̅m, a=632.94(5) pm, wR2=0.0590, 46 F2 values, seven variables) and Sc0.88Rh2Ga1.12 (a=618.91(4) pm, wR2=0.0284, 44 F2 values, six variables) have been refined from single crystal X-ray diffractometer data. Both gallides show structural disorder through Lu/Ga and Sc/Ga mixing. Temperature dependent magnetic susceptibility measurements showed Pauli paramagnetism for ScRh2Ga, ScPd2Ga, and LuRh2Ga and Curie-Weiss paramagnetism for TmRh2Ga. 45Sc and 71Ga solid state MAS NMR spectroscopic investigations of the Sc containing compounds confirmed the site mixing effects typically observed for Heusler phases. The data indicate that the effect of mixed Sc/Ga occupancy is significantly stronger in ScRh2Ga than in ScPd2Ga.


2000 ◽  
Vol 626 ◽  
Author(s):  
Svilen Bobev ◽  
Slavi C. Sevov

ABSTRACTWe have synthesized large single crystals of clathrate-II compounds with frameworks of silicon and germanium by employing mixed alkali metal countercations. The combinations of alkali metals are rationally selected in order to fit the different cages of the clathrate-II structure. This approach leads to the following stoichiometric and fully “stuffed” compounds: Cs8Na16Si136, Cs8Na16Ge136, Rb8Na16Si136 and Rb8Na16Ge136. The structures and the corresponding Si-Si and Ge-Ge distances are elucidated and established with high accuracy from extensive single crystal X-ray diffraction work. The compounds are stoichiometric, metallic, and are very stable at a variety of extreme conditions such as heat, concentrated acids, hydrothermal treatment etc. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these fully “stuffed” clathrates is consistent with the measured temperature independent Pauli paramagnetism, supported also by the conductivity measurements on single crystals and thermopower measurements on pellets. A new compound with novel clathrate-like structure forms when small and large cations are combined with tin. The new materials, A6Na18Sn46 (A = K, Rb, Cs), are made of clathrate layers and the interlayer space filled with Sn4-tetrahedra and alkali-metal cations. Its formula can be rationalized as A6Na6Sn34 + 3·Na4Sn4 (one clathrate layer and three tin tetrahedra). The compound is stable in air and is being currently tested at other conditions. Detailed measurements of its transport properties are under way.


1970 ◽  
Vol 48 (24) ◽  
pp. 2930-2936 ◽  
Author(s):  
F. T. Hedgcock ◽  
T. W. Raudorf

Electron spin resonance (ESR) measurements have been made on a phosphorus-doped silicon specimen (n = 1.38 × 1019/cc) in the liquid helium temperature range. A single line with a g factor of approximately 2 was observed for resonant magnetic fields of 540, 3230, and 12 590 G at 1517, 9010, and 35 200 MHz respectively. The experimentally determined magnetization is compared with the magnetizations expected from the following sources: (a) un-ionized charge carriers or local magnetic moments obeying a Curie law, (b) mobile carriers experiencing an exchange interaction with local magnetic moments, and (c) mobile charge carriers showing only Pauli paramagnetism. The magnetization derived from the ESR data exhibits a linear dependence with magnetic field and no temperature dependence. This is consistent with the Pauli paramagnetism expected for mobile charge carriers in the absence of any interaction with local moments.


2011 ◽  
Vol 66 (12) ◽  
pp. 1241-1247
Author(s):  
Patrick R.N. Misse ◽  
Richard Dronskowski ◽  
Boniface P. T. Fokwa

Powder samples and single crystals of the boride phases MxRh7−xB3 (M = Cr,Mn, Ni; x ≤ 1) have been synthesized from the elements using an arc-melting furnace under purified argon atmosphere in a water-cooled copper crucible. The new phases were characterized from single-crystal and powder X-ray diffraction, as well as semi-quantitative EDX measurements. The obtained phases crystallize in the hexagonal Th7Fe3 structure type (space group P63mc, no. 186, Z = 2). In all cases (M = Cr, Mn, Ni), M is found to preferentially mix with rhodium at only one (6c) of the three available rhodium positions. Pauli paramagnetism was observed in CrxRh7−xB3 (x < 1), whereas both Pauli and temperature-dependent paramagnetisms were found in NiRh6B3.


2001 ◽  
Vol 56 (7) ◽  
pp. 598-603 ◽  
Author(s):  
◽  
Gunter Kotzyba ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen

Abstract New intermetallic compounds EuAgCd and YbAgCd were synthesized in quantitative yield by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. Both com­ pounds were investigated by X-ray diffraction on powders and single crystals: KHg2 type, Imma, a = 490.41(8), b = 771.0(1), c = 834.4(2) pm, wR2 = 0.0624, 255 F2 values, 12 variables for EuAgCd, and MgZn2 type, Pb3/mmc, a = 584.66(5), c = 946.83(9) pm, wR2 = 0.0502, 187 F2 values, 11 variables for YbAgCd. Owing to the very small difference in scattering power, no long range ordering of the silver and cadmium atoms is evident from the X-ray data, although Ag-Cd ordering is expected. The silver and cadmium atoms randomly occupy the mercury and zinc positions of the KHg2 and MgZn2 type structures, respectively. In EuAgCd the [AgCd] substructure consists of strongly puckered, orthorhombically distorted Ag3 Cd3 hexagons, while a three-dimensional network of face-and comer-sharing tetrahedra is observed in YbAgCd. The rare earth atoms fill the space between the Ag3 Cd3 hexagons (EuAgCd) or within the three-dimensional tetrahedral network (YbAgCd). Magnetic susceptibility measurements in­ dicate Pauli paramagnetism for YbAgCd and Curie-Weiss behavior above 60 K for EuAgCd with an experimental magnetic moment of 7.82(3) μB/Eu indicating divalent ytterbium and europium. Ferromagnetic ordering at Tc = 28.0(5) K is observed for EuAgCd. At 2 K and 5 T the saturation magnetization is 5.85(5) μB/Eu.


2017 ◽  
Vol 72 (11) ◽  
pp. 855-864 ◽  
Author(s):  
Fabian Eustermann ◽  
Matthias Eilers-Rethwisch ◽  
Konstantin Renner ◽  
Rolf-Dieter Hoffmann ◽  
Rainer Pöttgen ◽  
...  

AbstractThe germanides RE3Pt4Ge6 (RE=Y, Pr, Nd, Sm, Gd–Dy) have been synthesized by arc-melting of the elements followed by inductive annealing to improve the crystallinity and allow for structural order. The compounds have been studied by powder X-ray diffraction; additionally the structure of Y3Pt4Ge6 has been refined from single-crystal X-ray diffractometer data. It exhibits a (3+1)D modulated structure, indicating isotypism with Ce3Pt4Ge6. The crystal structure can be described as an intergrowth between YIrGe2- and CaBe2Ge2-type slabs along [100]. Temperature-dependent magnetic susceptibility measurements showed Pauli paramagnetism for Y3Pt4Ge6 and Curie-Weiss paramagnetism for Pr3Pt4Ge6 and Nd3Pt4Ge6. Sm3Pt4Ge6 exhibits van Vleck paramagnetism, while antiferromagnetic ordering at TN=8.1(1) K and TN=11.0(1) K is observed for Gd3Pt4Ge6 and Tb3Pt4Ge6, respectively.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Naohiro Fujita ◽  
Daisuke Matsumoto ◽  
Yuki Sakurai ◽  
Kenji Kawahara ◽  
Hiroki Ago ◽  
...  

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